42A16 Fourier coefficients, Fourier series of functions with special properties, special Fourier series {For automorphic theory, see mainly 11F30} 2804
42A32 Trigonometric series of special types (positive coefficients, monotonic coefficients, etc.) 695
42A63 Uniqueness of trigonometric expansions, uniqueness of Fourier expansions, Riemann theory, localization 215